Why should total hip arthroplasty (hip replacement) be performed?
The hip is replaced for three reasons:
- distortion or
- to protect other joints
Pain due to joint damage is often the overwhelming symptom when deciding to replace a hip. It can be continuous, dominate every facet of life and make physical activity nearly impossible. Sometimes the hip may be deformed so that the body leans forward or the head may be submerged into the acetabulum (a condition known as “protrusio acetabuli”). The presence of a stiff hip may also in some cases burden the lumbar spine. Certain inflammatory conditions can affect both the lumbar spine and the hips. Ankylosing spondylitis is one such example. In this case the spine is mostly affected, but the hips can also be severely affected. Hip replacement may therefore in this case protect and relieve the spine.
Do I need a total hip arthroplasty?
You may need total hip arthroplasty – sometimes called total hip replacement – if your hip joint is damaged by arthritis. This damage is usually caused by osteoarthritis but can also be due to other types of arthritis, such as rheumatoid arthritis or post-traumatic stress. Surgery is not required for all patients with hip arthritis, but is recommended only when the pain and disability caused by it have significant effects on daily activities. Your doctor will usually try to relieve you with other treatments before offering you the surgical solution (painkillers, a walking cane, physiotherapy and more). And remember that you, the patient, are always the one making the final decision on whether your arthritis is severe enough to require a total hip replacement.
What can I expect from a total hip arthroplasty?
The main benefit of surgery is the elimination of pain. You will usually experience pain relief immediately after surgery. You will also gain much greater mobility, greater range of motion in your hip and a better quality of life. You should always remember that an artificial joint is never as good as your normal hip when it was healthy. There are restrictions.
Preparing for surgery
Total hip arthroplasty is a major surgery and any patient can assist in his recovery by being as prepared as possible for the effects. The best way to make the surgery as easy as possible for your surgeon, anesthesiologist and yourself is to be in a good general health condition before surgery, even with a sore hip. The items listed below can be very useful.
STOP SMOKING: Smokers are more vulnerable to respiratory complications during anesthesia and respiratory infections post-operatively. This can lead to prolonged bed rest and delay the patient’s progress.
LOSE WEIGHT: An overweight patient is more difficult to operate than a normal-weight one. The hip is covered by a larger mass of soft molecules, so more soft molecules need to be cut to reveal the hip, which leads to greater bleeding. It is also physically more difficult for surgeons (heavier work) to handle the lower extremity during surgery. Many overweight patients are also more vulnerable to respiratory problems during anesthesia. Patients should lose as much weight as possible. Less weight will also subject future arthroplasty to lighter loads.
MEDICATIONS: The prescribed medications for heart conditions or arterial hypertension should be taken systematically, so that the patient is in the best possible condition for the operation.
EXERCISE: Patients should try to do whatever physical exercise they can; the fitter they are, the easier it is for them to return to normal activity after surgery. The hospital physiotherapist can recommend exercises to strengthen specific muscle groups in the body, for example the arms, so that they can support the body after surgery.
Small home changes may be necessary to prepare the return after surgery. For example seats cannot be too low, for the basins you may need to use a special lifting seat and beds should not be too soft or too low. Your surgeon will provide you with the necessary information.
ON HOSPITAL ADMISSION
Total arthroplasty may be performed under general or regional anesthesia. As with other major surgeries, the patient should be evaluated prior to surgery to make it clear that he/she is in good health condition for surgery. A full medical history is usually obtained and various laboratory tests are performed. Examples of such tests are listed below:
HEMATOLOGICAL TESTS: Hematocrit, electrolytes etc. Blood examination will also be performed for blood cross-matching, so that blood is available, in case transfusion is required.
URINARY TESTS: It is necessary to check for possible urinary tract infection before surgery. If this is the case, it is very likely that total arthroplasty will be postponed, as it may otherwise be contaminated by an existing urinary tract infection.
CHEST X-RAY: Chest x-ray is required, in order to check for heart conditions or a possible respiratory infection, which can lead to respiratory distress during or after surgery.
HIP X-RAY: Necessary for the surgeon’s preoperative plan.
ECG: It examines the heart rate and other parameters.
Hospital admission can be scheduled on the day of surgery or on the previous one. Preventive medication will be administered to reduce the risk of venous thrombosis that can occur in the lower limb veins (deep vein thrombosis); a complication associated with major surgeries. The clots form more easily because during and after the surgery the patient is cramped and does not mobilize as needed. This leads to slow blood flow to the legs, which can lead to clot formation. The patient may also receive pre-anaesthetic drugs preoperatively, so that the patient can relax before anesthesia and surgery. Antibiotics are also administered to reduce the risk of a very minor but actual post-operative infection.
Preoperative screening is usually performed a few days before admission for surgery, while hospital admission is scheduled on the eve or early in the morning of surgery. Rarely, if there are any known, serious health problems (cardiological, respiratory, etc.), it may be advisable to be admitted to hospital 2-3 days earlier than usual to resolve these.
What happens on the day of surgery? You will probably be given a pill or injection to relax and avoid any pre-operative anxiety and stress (pre-anaesthetic drugs). In the operating room you will be administered anesthesia by the anesthesiologist. It may be general anesthesia (in this case you will fall asleep) or a local-regional anesthesia, such as epidural or dorsal anesthesia (which makes you feel numb in your waist and lower). Most patients today are operated on dorsal or epidural anesthesia and at the same time undergo mild sedation during the procedure, so that they do not hear or understand the effects. When you enter the operating room you will be placed on your side, on your healthy hip, in order to perform the back access surgery. Surgery involves the removal of the articular part of the hip joint and the introduction of an artificial prosthesis. It may be performed with the patient either lying in the supine position or on his/her side with the affected hip upwards, and the incision may be approximately 10 to 20cm. The size of the incision depends on the dimensions, general and local, of the patient, as well as the technique to be applied. Newer techniques, including the so-called Minimum Intervention Technique (MIS), generally require smaller incisions and surgical access, but are performed with specific criteria in selected patients. In general, the greater the thickness or fat around the joint, the greater the incision required, as the joint is more concealed and a disclosure should be made to allow the implants to be positioned correctly.
The surgeon cuts the skin and tissues (including the muscles and ligaments) below it to reveal the hip joint. The hip is then dislodged and the femoral head is removed with a special saw. Removal of the femoral head reveals the acetabulum. The acetabular articular bone is removed with special surgical tools called gills (which rotate rapidly and “eat” the articular bone). It is important to remove all affected bone leaving behind a healthy bone with adequate blood supply. The healthy bone will accept the implant much better than degenerated bone.
The first implant to be placed is the acetabular implant. Once this is inserted into the acetabulum, the femur implant is then implanted. Once the two implants are firmly positioned, the hip is again positioned (i.e., the femoral head enters the acetabulum) and the various layers of subcutaneous and skin layers are again stitched back into place. The new joint is held in place by surrounding muscles and soft molecules, which will strengthen as the wound heals.
It usually takes a period of about 40 days for the soft molecules to heal that were disrupted during surgery, and therefore this time will require the patient’s special attention. One or two small, plastic tubes may be inserted into the wound to drain the blood from the surgical site (drainage); these are usually removed within the first 24 to 48 hours of surgery. No matter how vigorously the surgeon tries to achieve hemostasis in the area of surgery, it is not possible to stop all the bleeding at the time of surgery. So nature will do the rest of the work during the first 24 hours after surgery by activating the body’s coagulation agents.
What is the new joint?
The normal hip is a cup-like ball joint. In the total hip arthroplasty, the part of the femur that comprises the head is cut-off and a new smaller one is inserted into the femoral bone through a stylet inserted into the femoral lumen. The acetabular surface (of the pelvis) is sculpted – rejuvenated to accommodate the new acetabulum, which will articulate (mate) with the implanted “ball” (femoral head).
The way the implants are stabilized in both the acetabular and the femur varies. Thus, acetabulum fixation has traditionally been performed with cement, a technique which is still used successfully in some cases. The usual practice, however, is cementless fixation. The acetabular implant (acetabular prosthesis) is specially formulated – processed on its surface, roughened and sometimes treated with a special coating (such as hydroxyapatite for example) to achieve bone-to-prosthesis interconnection. On the other hand, the femur is stabilized in the lumen of the femur either by the use of cement, which is still most commonly used for femoral prosthesis, just as often without the use of cement. In this case, the inter-connection of the prosthesis with the femoral bone is achieved by proper treatment of its porous surface and by coating it with special materials.
The acetabular implant, when mounted without cement, usually consists of titanium-based metal alloys, and a polyethylene (plastic) insert inside the joint, which is articulated with the head. When cement-fixed, the implant consists entirely of polyethylene (UHMWPE, very high molecular weight polyethylene). Newer techniques and inventions have led to the creation of acetylated inserts for the acetabulum, such as ceramic or metallic materials, which offer less friction and better durability and are commonly used at younger ages. The head may be metallic, when it is articulated with plastic or metal, or it may be ceramic when articulated with plastic or ceramic. The femoral pole is respectively made of metal alloys, either on the basis of titanium if no cement is required or on chromocobalt if cemented.
Sometimes it is preferable only to replace the surface of the femoral head, instead of total head replacement, in order to remove the smallest possible amount of bone and use a larger articular surface. This procedure is called surface arthroplasty, the articulated surfaces are metal-to-metal and is also used in younger people as it achieves a greater range of motion with a consequent better ability to perform sports activities and greater ease in the next surgery when and if required. However, metal-to-metal surface arthroplasty is not indicated in cases of osteoporotic bones, as femoral neck fracture may occur, while it is not preferred in young women of childbearing age, people with small skeletons, patients with allergies and other contra-indications, which the physician has to assess.
What happens after surgery?
When you leave the operating room you will usually have a vein catheter in your arm (for the administration of liquids and medicines) and one or two drainage tubes in your hip (to drain fluid and blood from the operated joint). You will be taken to the recovery room where you will remain until you recover – fully awake and in a stable hemodynamic state to be transported to your room. You will have a pillow between your legs to keep them apart (abduction pillow). You will be administered painkillers to relieve postoperative pain and other medicines to prevent vomiting, constipation and more.
The drainage tubes are usually removed after 24 to 48 hours. The next morning you will be able to turn around, sit on the bed and get up and walk with a stroller or a pair of crutches. There is a specific way to do all of these activities that will be explained in detail by your physiotherapist and your physician. How quickly you will return to your normal activity depends on many factors, including your age, the condition you were in before surgery, your general health and the condition of your other joints.
Physiotherapy and training
Physiotherapists will help you to move comfortably and will teach you the exercises you will need to strengthen your muscular system. They will explain what movements are allowed and which are prohibited the first days following a total hip arthroplasty. It is very important that you follow these rules. For example, you should avoid bending your hips (such as squats) and crossing your legs, as these movements can dislocate your hip. These restrictions usually apply, together with others, for the first two months after surgery. Physiotherapists will explain the right way to get out of bed, sit, walk, climb and descend and go to the toilet. You will need a lifting seat for the pelvis so that you will not squat and elastic knee socks to avoid venous thrombosis.
When can I leave the hospital?
Most patients are able to climb stairs and walk with assistance within the first 5-7 days, so they get discharged from hospital. The stitches are removed after 2-3 weeks, and the surgeon will ask to see you again, usually 40-50 days after surgery for a new X-ray examination.
What happens in the first weeks after surgery?
You will discover that you can bend your hip to your belly as much as you like, but it is important not to attempt to test your limits during the first days. You should be very careful during the first 8-12 weeks after surgery. You will most likely be able to drive a car after the first month and return to work at the same time, if your job does not require manual labor or a lot of commuting. Getting in and out of the car can be difficult at first. You may need to sit on your side at first and then bring your feet in. These will be explained to you by your hospital physiotherapist. You need to perform your exercises regularly. Walking, swimming (but not breast-stroke) and cycling are exercises that you may perform after 4-8 weeks. But you should avoid running on hard surfaces, sports that involve intense physical contact or sports that require a high competitive level as they put great force on your hip.
What are the long-term effects of total hip arthroplasty?
There are many different types of arthroplasty today. Some may be better than others, but there are many factors that influence the outcome and survival of the prosthetic joint. You should expect your arthroplasty to last at least 15 years. In younger patients less than 50 years of age, arthroplasty survives for fewer years because the patient’s demands are much greater and the joint stresses are greater.
Can there be complications?
Total arthroplasty is a major surgery and is associated with various complications. The risk varies, depending on the general state of the patient’s health and you should discuss the potential risks and complications with your surgeon.
After total hip arthroplasty, one possible complication is deep vein thrombosis (DVT) in the lower extremity veins. Fortunately, this complication is not common and is prevented by the use of special compression stockings and medication. In case it occurs, it is treated with the appropriate medication.
There is a more serious complication in which the clots can be detached from the lower limb veins (in some cases of DVT) and migrate to the lungs (pulmonary embolism, IP). IP is a very serious complication and can cause sudden death, but it is extremely rare.
The artificial joint can be dislocated, usually due to some incorrect or abrupt movement. This occurs in less than 1 in 20 cases and is restored back in place under anesthesia. Usually this is enough to stabilize the hip, but in some cases patients may need to perform extra exercises to strengthen the muscles around their hip or wear a special lumbar-femoral guardian for some time.
In order to prevent infections, special surgery rooms are used in which the air is renewed and the microbial load is reduced. Patients take antibiotics during and after surgery for the same reason. However, the risk of deep infection is present, but in less than 1 in 200 cases. And this is a serious complication because the artificial joint may need to be removed, in order to eradicate the infection. A new joint will be placed 6-9 weeks later.
It is of course important that the patient does not experience worse symptoms after the procedure than before. Although the complications are unusual, they still exist. It is therefore necessary for the patient to be fully informed before proceeding with the operation (i.e. ‘informed written consent’ of the patient).
The implications are theoretically numerous and varied. Most are of minor relevance and are associated with surgical interventions in general, rather than with total hip arthroplasty. For older patients, especially those over 80 years old, the chances of a complication are increased. In cases of revision of a total arthroplasty (that is, for a second or more time) there is also an increased risk of complications.
Complications may occur during or after surgery. They can also be divided into those that occur as a result of any major surgery (general complications) and those which are specific to total hip arthroplasty (specific complications).
Infection (<0.5%): This will often be treated with powerful antibiotics although sometimes, revision of arthroplasty may rarely be required.
Hematoma, trauma or internal injury: Sometimes there may be a blood collection in the surgical field which may also, fortunately, rarely need to be drained and this requires a minor wound incision.
Wound Dehiscence: This means that the surgical wound may rupture along a surgical incision and will need to be re-stitched.
Drainage trapping (extremely rare): the small plastic drainage tube can be trapped inside the wound and may need re-opening to remove it.
Urinary Complications: It is quite common for patients after surgery to have difficulty in urination. This is the result of the difficulty that some patients have in urinating when they are lying down, which probably preceded the surgery. It is more common in men with prostate hypertrophy. To treat these problems, a catheter is sometimes inserted to empty the bladder for a few days after surgery.
Gastrointestinal complications: They can sometimes be the result of anesthesia, electrolyte disorders or surgery size. The intestine has been inactive for a few days. This is usually treated with appropriate medication (laxatives). Very rarely a small tube can be inserted through the nose or mouth to drain stomach fluids while the patient should not be fed at that time. This is performed in cases of ileus, but they are extremely rare in total hip arthroplasty. It should be noted that both reduced patient mobility and analgesic medications can cause constipation which is successfully treated with laxatives.
Complications of the cardiovascular system: Surgical stress can sometimes be so severe that it can cause a heart attack. However, this is extremely rare and occurs in less than 1 in 1000 patients. Also extremely rare is the complication of the formation of a small clot in the heart that will cause a stroke. The most common complication of the cardiovascular system, though not particularly common, is deep vein thrombosis. This is precisely the reason drugs are used to avoid this complication, either in the form of subcutaneous injections or oral. For the same reason, special compression stockings are used to aid blood circulation, while the rapid mobilization of the patient also plays an important role.
Respiratory complications: They usually occur as a result of anesthesia and prolonged bedding. Patients with previous heart or respiratory problems are more prone to such complications.
Death (less than 1 in 10,000 patients): It is usually caused by a variety of factors and causes related to respiratory or heart problems that pre-existed and are aggravated by surgery.
Dislocation (up to 5%): In this complication the femoral head slips out of the acetabulum. Anesthesia is usually needed to restore the dislocation followed by a period of increased care or possibly the use of a special orthopedic guardian to avoid a new dislocation. Very rarely, new surgery may be needed, usually in cases of recurrence.
Fracture (less than 1% for initial surgery and about 3% for revision surgery): This usually occurs during surgery as a result of the high forces the bone undergoes in surgery. The fracture may not be detected during the operation but can be diagnosed on the first X-ray taken after the operation. If detected during surgery, the surgeon usually addresses the issue immediately, either by using reinforcing wires or screws and plates. If the fracture is diagnosed after surgery, another surgery or prolonged bed rest may be necessary to physically heal the fracture.
Nerve injury during surgery (max. 2%): As the nerves are located too close to the hip joint it is not rare that they can be injured. Most often resuscitation is achieved automatically over a long period of time, usually around 1 year. Very rarely, neurological problems may not be restored, a complication that will lead to motor problems for the patient.
Inferior pain around the major trochanter: Known as “trochanteritis”, it is characterized by localized pain on the outer surface of the hip. It has no functional importance, but it can be annoying to the patient. It may last for long periods of time. This complication was more common in the past when trochanter osteotomy was performed during total hip arthroplasty, a technique that is not currently used, resulting in major trochanter bursitis or otherwise “trochanteritis”, which is a very rare complication nowadays.
Translocation of the implant: In this case, the artificial hip changes position within the joint. It is very rare, but occasionally implants can be immersed inside the bone. A femoral implant, for example, can be immersed in the femur while an acetabular implant may be immersed in the acetabulum. It is usually the result of the patient’s supporting bone being weak and may require new surgery.
Leg length discrepancy: One of the most common complications of total hip arthroplasty (up to 6%) is the development of leg length discrepancy. It is more common for the operated leg to be longer; sometimes there is a need for a shoe lift on the other leg to reverse this difference. However, it must be made clear that it is the surgeon’s primary concern to measure the legs during and at the end of the procedure so as to create a balance which is not always entirely possible. Many methods have been devised to avoid this discrepancy, but none are completely safe.
Nerve damage that occurs after surgery: Bleeding may continue after surgery although this is rare. However, blood accumulated around a nerve can cause damage. The result may be the same as if the nerve was injured during surgery.
Vascular Damage (0.4% for initial surgery and less than 1% for revision surgery): As with the nerves, large vessels around the hip joint and can be injured during surgery. However, this complication is extremely rare.
Replacement of an artificial joint with another (arthroplasty revision)
The most common cause of total arthroplasty failure is aseptic loosening. This can happen at any time but it is usually observed 15 years later. It usually causes pain and the hip becomes unstable. Then, a new arthroplasty procedure called revision will be required. This type of surgery has been significantly improved in recent years. Artificial joints can be replaced as many times as needed, though the results are less satisfactory each time.